In March 2006, a dead, juvenile, male bottlenose dolphin (Tursiops truncatus) was found in the marsh in Charleston, South Carolina. During necropsy, an enterolith was discovered completely obstructing the intestinal lumen. Further examination of the enterolith revealed a stingray spine nidus. The stingray spine was identified as belonging to the Southern stingray (Dasyatis americana). Interactions with stingrays are not uncommon for marine mammals2,7-8,16; however, linking the postmortem presence of stingray spines to the cause of death can be difficult. In this particular case, the state of decomposition hindered external and internal observations of spine penetration and migration. Enteroliths have been found in many terrestrial mammals and humans1,4,6,9,11,14,17, but they have apparently not been reported in bottlenose dolphins. Enterolithiasis has been linked to diet5-6, genetics4,6, alkaline intestinal environments3,10,13,15, and, as in this particular case, the ingestion and retention of foreign bodies.6,9,12,14 Most terrestrial enteroliths are composed primarily of struvite (magnesium ammonium phosphate)5-6,9,12,14; however, the composition of this enterolith from a bottlenose dolphin was primarily calcium phosphate carbonate. This case study emphasizes the need for thorough post-mortem examinations of carcasses, and provides an interesting comparison of the enterolith mineral composition between marine and terrestrial animals.
The authors would like to thank R. Sayre for assistance with the stranding response and necropsy of this bottlenose dolphin, F. Townsend for his veterinary expertise, W. McFee for his necropsy and sample analysis expertise, B. Roumillat Sr. for species identification of the stingray spine, and B. Roumillat Jr. for radiographs of the enterolith.
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